Electromagnetic relays



Aug. 13, 1968 B. s. BARNABY E AL 9 3 ELECTROMAGNET I C RELAYS Filed Aug. 10, 1966 4 Sheets-Sheet l Fig.1

BY 4, 41 macho HI 702N575 Aug. 13, 1968 B. s. BARNABY E AL ELECTROMAGNETIC RELAYS 4 Sheets-Sheet 2 Filed Aug. 10, 1966 V! N 2 5% M907 My 2 .m WW? m 5 4 7 m a m 9 .1 m B W I O WS 1968 B. s. BARNABY ET AL 3,397,371

' ELECTROMAGNETIC RELAYS I Filed Aug. 10, 1966 4 Sheets-Sheet 5 Fig 3 90 LZWLQ, 41.44.] 94-30.

Aug. 13, 1968 B. s. BARNABY ET 3,397,371

ELECTROMAGNETIC RELAYS Filed Aug. 10, 1966 4 Sheets-Sheet 4 K mm 15a 2b, "12c '1 no mm 1m 12d 102 Fig.4

United States Patent Office 3,397,371 Patented Aug. 13, 1968 3,397,371 ELECTROMAGNETEC RELAYS Bernard Sydney Barnaby, Ware, Peter William Ward, Hatch End, and Peter H. Morcombe, Newton Aycliife, England, assignors to The General Electric Company Limited, London, England, a British company Filed Aug. 10, 1966, Ser. No. 571,551 Claims priority, application Great Britain, Aug. 12, 1965, 34,583/ 65 12 Claims. (Cl. 335112) ABSTRACT OF THE DISCLOSURE An electromagnetic relay has two operated positions on either side of a normal stable position, the armature being mounted on the center limb of an E-shaped core so as to rock towards one or the other outer limb selectively. The contact units and the remainder of the relay are separately mounted on a printed circuit board the conductors of which constitute one contact of each contact unit.

This invention relates to electromagnetic relays.

According to the present invention, an electromagnetic relay incorporates an electromagnet assembly wherein an armature engages and is arranged to pivot on the end of the centre limb of a generally E-shaped ferromagnetic core and is movable electromagnetically and selectively from a normal stable position to either one of two operated positions in each of which it causes different ones of at least two contact units of the relay to be actuated.

Each said contact unit may comprise an electric contact member and an electric contact spring which is arranged to make electric connection with that contact member upon the actuation of that contact unit.

Each said contact unit may have its contact member carried by a common electric insulating member and its contact spring supported by a portion thereof being fixedly mounted relative to this insulating member. The electromagnet assembly also may be mounted on this insulating member.

According to a feature .of the present invention, in an electromagnetic relay an electromagnet assembly is mounted on an electric insulating member and incorporates a pivoted armature that is movable electromagnetically and selectively from a normal stable position to either one of two operated positions in each of which it causes at least one of a plurality of contact springs supported by said insulating member to make electric connection with an associated contact member carried by that insulating member.

Each contact member may comprise a printed circuit conductor formed on said insulating member. (The term printed circuit conductors used herein refers to electrical conductors formed as a metallic pattern on an electrical insulating substrate, and it is not intended that this term be limited to the case in which the metallic pattern is obained by an actual printing process.)

There may be a plurality of further printed circuit conductors on the insulating member and each contact spring may be mounted so as to be in intimate electrical engagement at all times with a different one of these further printed circuit conductors.

Preferably the electromagnet assembly is detachably mounted on the insulating member. Thus, the electromagnet assembly may be carried by a frame, housing or other supporting means that has one or more portions abutting one side of the insulating member and a plurality of resilient lug portions which extend through apertures in the insulating member and which bear against this member to grip it from the other side.

According to another feature of the present invention,

an electromagnetic relay comprises an electric insulating member which carries two groups of electric contact units, and an electromagnet assembly mounted on said insulating member and incorporating a pivoted armature which is movable electromagnetically and selectively from a normal stable position in which none of said contact units are actuated to either one of two operated positions in each of which the contact units of a different one of said groups are actuated by that armature.

Preferably said operated positions of the armature are on opposite sides of its normal position.

An embodiment of electromagnetic relay in accordance with the present invention comprises a pivoted armature having a normal stable position and two operated positions which are .on opposite sides of this normal position, at least two electric contact units different ones of which are arranged to be actuated by the armature in each of its operated positions and each of which is adapted to store energy upon its actuation for subsequently restoring the armature to said normal position, and an electromagnet system by which the armature is movable electromagnetically and selectively to either operated position and which incorporates means arranged to damp the armature electromagnetically so that any overshoot of said normal position is insufiicient to cause the actuation of the one or more contact units associated with the other operated position.

Each said contact unit may comprise a contact member and a contact spring of which a portion is displaceable by the armature to make electric connection with that contact member.

The armature and the electromagnet system may be incorporated in an electromagnet assembly that is mounted on an electric insulating member which also carries the contact units.

Two electric switching assemblies which each employs a plurality of electromagnetic relays in accordance with the present invention will now be described, by way of example, with reference to the five figures .of the accompanying drawings in which:

FIGURE 1 is a plan view of part of the first switching assembly to be described,

FIGURE 2 is a side elevation, partly in section, of one of the electromagnetic relays employed in the switching assembly of FIGURE 1,

FIGURES 3 and 4 respectively show top and underneath plan views of part of the second switching assembly to be described, and

FIGURE 5 is a side elevation, partly in section at the line VV in FIGURE 3, of one of the electromagnetic relays employed in the switching assembly of FIGURES 3 and 4.

These two switching assemblies form the subject matter of our copending United States patent application, Ser. No. 571,482, filed Aug. 10, 1966 and assigned to the assignee of the present application.

In each of the switching assemblies to be described, a generally rectangular board of electrical insulating material carries ten input paths which each comprises four printed circuit conductors on the top surface of the board, a further ten printed circuit conductors on the said top surface of the board, one for each input path, ten output paths which each comprises four printed circuit conductors on the under surface of the board and fifty electromagnetic relays which are arranged in a matrix of five columns and ten rows on the said top surface of the board. The ten input paths are associated with the ten rows of relays respectively and the five pairs of adjacent output paths are associated with the five columns of relays respectively.

Each of the said relays is arranged, as will be hereinafter described, so that in each of two operated states of 3 that relay a different one of the two associated output paths has its four conductors connected to the four conductors respectively of the associated input path, and so that in the nonoperated state of that relay such connections do not exist.

Reference now should be made to FIGURE 1 which shows part of the first switching assembly to be described. This part comprises one corner of the board 1 of insulating material, portions of the printed circuit conductors 3a to 3d, 411 to 4d and 5a to 5d of three input paths 3, 4 and 5 on the top surface 2 of the board 1, portions of the printed circuit conductors 6a to 6d, 7a to 7d, 8a to 8d and 9a to 9d of four output paths 6, 7, 8 and 9, the six relays 10, 11, 12, 13, '14 and that are associated with both the input paths 3, 4 and 5 and the pairs of output paths 6, 7; and 8, 9 and portions of the three printed circuit conductors 16, 17 and 18 that are associated with the input paths 3, 4 and 5 respectively.

The said two operated states of each relay, for example, the relay 12, are each obtained by energising a different one of two windings 19 and 20 of that relay with direct current of suitable magnitude. As will be hereinafter described, the winding -19 controls the making of connections between the conductors 3a to 3d and the conductors 6a to 6d while the winding 20 controls the making of connections between the conductors 3a to 3d and the conductors 7a to 7d.

' The relays of this switching assembly, such as the relays 10 to 15, are identical, the construction of the relay 12 being illustrated, by way of example, in FIGURE 2 to which reference now should also be made. This relay 12 has an electromagnet assembly which is detachably mounted on the board 1 and which incorporates a generally E-shaped ferromagnetic core 26, an armature 27 arranged to pivot on the centre limb 28 of the core 26, the windings 19 and 20 which embrace the two outer limbs 29 and 30 of the core, and a housing 31 which carries the core and the windings. The armature 27 spans and normally is supported adjacent its two ends 58 and 59 by two groups of contact springs respectively which hold the armature in engagement with the end of the centre limb 28 of the core 26 and of which only the contact spring 32 of one group and the contact spring 33 of the other group can be seen. Each group comprises four identical contact springs which are parallel to one another and side by-side. The armature 27 has a shallow channel 62 across one face mid-way between its ends, this channel cooperating with the end of the centre limb 28 of the core 26 to locate the armature. The armature is shaped so that normally its two ends 58 and 59 are adjacent to and substantially equidistant from the ends of the outer limbs 30 and 29 respectively of the core 26. Strips 63 and 64 of electrical insulating material are provided across the ends 58 and 59 of the armature 27 to prevent these ends actually engaging the ends of the outer limbs 29 and 30 when the armature pivots. Actual engagements between the armature 27 and the two groups of contact springs having the contact springs 32 and 33 are prevented by two bars 65 and 66 of electrical insulating material that are attached to the armature.

Each contact spring of the group including the contact spring 32 has one end held by one or more rivets (not shown) in intimate engagement with a different one of four isolated conductor areas 34, 35, 36 and 37 formed on the top surface 2 of the board 2. Each contact spring of the group including the contact spring 33 similarly has one end held in intimate engagement with a different one of another four isolated conductor areas 38, 39, 40 and 41 formed on the surface 2. The four contact springs of one group are alined with the four contact springs respectively of the other group and have their free ends adjacent to the free ends of the contact springs of this other group.

The three contact springs which engage the conductor areas 34, and 36 are connected through the board 1 by their rivets (not shown) to the conductors 6a, 6b and 60 respectively of the output path 6. Similarly the three contact springs which engage the conductor areas 39, 40 and 41 are connected through the board 1 to the conductors 7b, 7c and 7d respectively of the output path 7. Two terminal pins 42 and 43 are mounted on the board 1 so as to be in intimate engagement with the conductor areas 37 and 38 respectively. Another two terminal pins 44 and 45 are mounted on the board 1 so as to be in intimate engagement with the conductor 16. Two furher terminal pins 46 and '47 are mounted on the board 1 so as to be in intimate engagement with the conductors 6d and 7a respectively. All the terminal pins 42 to 47 project from the top surface 2 of the board 1.

The housing 31 is moulded from an electrical insulating material such as the acetal resin sold under the registered trademark Delrin. This housing is in the form of a generally rectangular box 31a which is closed at one end by a wall 31b and which has two spaced bobbins 31c and 31d for the windings 19 and 20 formed'on this wall. The housing 31 is detachably mounted on the board 1 so that this board closes the open end of the box 31a. Thus four lugs, such as the lugs 48 and 49, at the four corners of the box 31a are sprung into locating holes in the boardl, such as the holes 50 and 51. The core 26 comprises two generally U-shaped stampings 26a and 26b formed from metal strip comprising an alloy of 45% nickel and 55% iron. The three limbs 28, 29 and 30 of the core 26 are tight fits in apertures through the bobbins 31c and 31d and the wall 311) of the housing 31. The end faces of these limbs 28, 29 and 30 all lie in substantially the same plane and are just proud of the surface of the wall 31b that is inside the box 31a. The portions of the core 26 that are between the limbs 28 and 29 and between the limbs 28 and 30 are embraced by copper rings 52 and 53 respectively.

The winding 19 at one end of the housing 31 is connected between two terminal pins 54 and 55 which are moulded in the opposite end of that housing. Similarly the winding 20 is connected between two terminal pins 56 and 57. The terminal pins 54 and 55 are directly connected to the terminal pins 42 and 46 respectively while the terminal pins 56 and 57 are directly connected to the terminal pins 47 and 43 respectively. A rectifier element 21 is connected between the terminals 42 and 44 so as to be in series with the winding 19 in a circuit which extends from the conductor 6d to the conductor 16. A rectifier element 22 is connected between the terminals 43 and 45 and thus is in series with the winding 20 in a circuit which extends from the conductor 7a to the conductor 16. The rectifier elements 21 and 22 are each poled so as to present a low impedance to conventional current flow from its associated one of the conductors 6d and 7a to the conductor 16.

When it is required to make connections between the conductors of any one of the input paths, for example, the input path 3 and the conductors of any one of the output paths, for example, the output path 7, a suitable direct current supply is connected between the conductor 16 associated with this input path 3 and the conductor 7a of this output path 7 so that these conductors 16 and 7a are at relatively negative and positive voltages respectively. Thus the winding 20 is energized via the rectifier element 22, the other rectifier elements, such as the rectifier elements 23 and 24 preventing current flow from this supply through any of the other relay windings. Upon the energisation of the Winding 20, the adjacent end 58 of the armature 27 is attracted to the outer limb 30 of the core 31 and the armature pivots on the centre limb 28 of that core. Consequently the other end 59 of the armature 27 moves towards the board 1 thereby causing the group of contact springs including the contact spring 33 to make connection with the conductors 3a to 3d of the input path 3. In this way direct connections are made between the conductors 3b, 3c and 3d of the input path 3 and the conductors 7b, 7c and 70. respectively of the output path 7 While the winding 20 is connected directly between the conductors 3a and 7a. This last mentioned connection enables the winding 20 to be energised independently of the conductor 16 so as to make this conductor available for use in selectively energising any other one of the associated windings such as the windings 60 and 61 of the relay 15.

The energy stored by the. deflected contact springs 33 serves to restore the armature 27 to its normal position, as shown in FIGURE 2, when the supply of ,energisiug current to the winding 20 is discontinued. The co er rings 52 and.53 are provided to retard the decay of magnetic flux in the outer limbs 29 and 30 of the core 26 that occurs upon the deenergisation of the windings 19 and 20 respectively. In this way the armature 27 is damped during restoration so that it cannot suificiently overshoot the normal position to cause the engagement of the conductors 3a to 3d by the other group of contact springs.

, It will be appreciated that in each relay, for example, the relay 12, the armature 27 has two operated positions which are on Opposite sides of its normal position and in each of which a different one of the two groups of contact springs is deflected into engagement with the conductors 3a to 3b of the input path 3.

The end of the centre limb 28 of the core 26 may be bevelled (not shown) or the channel 62 across the armature 27 may be shaped so that when that armature is moved into either of its operated positions, engagement with this centre limb is maintained over an appreciable surface area of the armature. This ensures that the magnetic reluctance between the armature 27 and the centre limb 28 of the core 26 does not increase appreciably when the armature is moved from said normal position to either operated position.

Reference now should be made to FIGURES 3 and 4 which respectively show top and underneath views of part of the second switching assembly to be described. This part comprises a portion of the board 68 of insulating material, portions of the printed circuit conductors 69a to 69:2 and 70a to 70d of two input paths 69 and 70, portions of the printed circuit conductors 71a to 71d and 72a to 72d of one pair of adjacent output paths 71 and 72, portions of printed circuit conductors 73 and 74 which are associated with the input paths 69 and 70 respectively, the relay 75 which is associated with the input path 69 and the output paths 71 and 72 and part of the relay 76 which is associated with the input path 70 and the output paths 71 and 72. (In FIGURE 3 the relay 76 is illustrated with its electromagnet assembly removed so as to show the contact springs.)

The said two operated states of each relay, for example the relay 75, are each obtained by energising a dilferent one of two windings 77 and 78 of that relay with direct current of suitable magnitude. The winding 77 controls the making of connections between the conductors 69a to 69d and the conductors 71a to 71d while the winding 78 controls the making of connections between the conductors 69a to 69d and the conductors 72a to 72d.

The relays of this switching assembly are identical, their construction being illustrated in FIGURE 3 and also in FIGURE 5 to which reference now should also be made and which represents the relay 75. Each relay has two groups of four identical contact springs of which only the contact springs 79 and 80 of the two groups of the relay 75 can be seen (FIGURE 5). The contact springs 81, 82, 83 and 84 and the contact springs 85, 86, 87 and 88 of the two groups of the relay 76 are shown in FIGURE 3. Each relay, for example, the relay 75 also has an electromagnet assembly 89 which is detachably mounted on the top surface 90 of the board 68 and which incorporates a generally E-shaped ferromagnetic core 91, an armature 92 arranged to pivot on the centre limb 93 of this core, the windings 77 and 78 which embrace the two outerlimbs 94 and 95 of this core, and a housing 96 which carries the core and the windings.

The relay 75- differs from the relay 12 described above with reference to FIGURES.1 and 2 in the following respects:

A generally rectangular plate 97 of electrical insulating material stands on the top surface of the board 68 and supports the housing 96. The corresponding plate 98 ofthe relay 76 is illustrated in FIGURE 3. Each of the contact springs such as the contact springs 79 and 80 has one end clamped between the plate 97 and the housing 96 and has its other end extending into an aperture 99 through the plate. Each contact spring, for example, the contact spring 80 has a tongue portion 100 that extends through alined "apertures in the plate 97 and the board 68 and is connected electrically to one conductor 720 of the output path 72 that is associated with its group of contact springs. In this way, the four contact springs of the group including the contact spring 80 are connected to the conductors 72a, 72b, 72c and a further printed circuit conductor 101 respectively on the under surface 102 of the board 68. Similarly, the four contact springs of the group including the contact spring 79 are connected to the conductors 71a, 71b, 71c and a further printed circuit conductor 103 respectively on the surface 102. The contact spring 80, like every other contact spring of the relay 75, cooperates with a locating stud 104 formed on the plate 97. The conductors 69a, 69b, 69c and 69d extend across the board 68 and under the plate 97 so that each passes immediately under but at a distance from the free end of .a different one of the four contact springs of each group. Thus the conductor 69c passes under the contact springs 79 and 80.

The housing 96 and the plate 97 are located and held on the board 68 by a bracket 105 of mild steel and a spring strip 106. Each of the end arms 105a and 1050 of this bracket, for example, the end arm 105a, is formed with :a slot 107 into which extend outwardly projecting parts 108 and 109 of the housing 96 and the plate 97 respectively. These end arms 105a and 1050 are provided with hook shaped lugs 110 and 111 which extend through. apertures 112 and 113 in the board 68. The spring strip 106 engages with these lugs 110 and 111 and with a printed conductor area 114 on the under surface 102 of the board 68 to hold the bracket 105 and hence the housing 96 and the plate 97 in position. The core 91 comprises two generally U-shaped stampings 91a and 91b which are welded to the cross-arm 10512 of the bracket 105. These stampings 91a, 91b and the armature 92 are of the nickel iron alloy known as permalloy-B.

- The winding 77 is connected between an adjacent pair of terminal pins 115 and 116 which are moulded in the housing 96. Similarly the winding 78 is connected between a pair of terminal pins 117 and 118 which are moulded in the housing 96. These terminal pins 115, 116, 117 and 118 pass through four apertures in the board 68 that ext-end through the conductors 103, 71d, 72d and 101 respectively and have their ends soldered or otherwise connected electrically to these conductors. The terminal pins 115 and 118 also are connected via individual rectifier elements 119 and 120 to the conductor 73. Each of these rectifier elements 119 and 120 is poled to present a low impedance to conventional current flow from its associated one of the terminal pins 115 and 118 to the conductor 73.

When it is required to make connections between the conductors of any one of the input paths, for example, the input path 69, and the conductors of any one of the output paths, for example, the output path 72, a suitable direct current supply is connected between the conductor 73 associated with this input path 69 and the conductor 72d of this output path so that these conductors are at relatively negative and positive voltages respectively. Thus the winding 78 is energised via the rectifier element 120 thereby causing the adjacent end 121 of the armature 92 to be attracted to the outer limb 95- of thecore 91 and the armature to pivot on the end of the centre limb 93 of that core. The other end 122 of the armature 92 moves towards the board 68 thereby deflecting the group of contact springs including the contact spring 80 into engagement with the conductors 69a to 69d of the input path 69. Thus direct connections are made between the conductors 69a, 6% and 690 and the conductors 72a, 72b and 720 while the winding 78 is connected directly between the conductors 69d and 720.. The last mentioned connection enables the winding 78 to be energised independently of the conductor 73 so as to make this conductor available for use in selectively energising either winding of any other relay (not Shown) in the same row as the relay 75.

The energy stored in the deflected contact springs serves to restore the armature 92 to its normal position when the supply of energising current to the winding 78 is discontinued. If desired, the armature 92 may be damped electromagnetically during restoration by means of copper rings (not shown) around the two parts 91a and 91b of the core 91.

We claim:

1. In an electromagnetic relay the combination of a pivoted armature, a plurality of electric contact springs which bias the armature to a normal stable position, a plurality of electric contact members, an electromagnet system by which the armature is movable electromagnetically and selectively from said normal position to either one of two operated positions which are on opposite sides of said normal position and in each of which different ones of the contact springs are displaced by the armature to engage predetermined ones of the contact members, and damping means comprising members of electrically conducting material, such as copper, magnetically coupled with said electromagnet system so as to retard the decay of flux therein.

2. An electromagnetic relay comprising a ferromagnetic core having a center limb and two outer limbs one on each side of the center limb, an armature which engages and is arranged to pivot on the end of the center limb of the core, bias means which biases the armature to a normal stable position, electromagnet means for moving said armature electromagnetically and selectively from said normal position to either one of two operated positions, at least two contact units, at least one of which is actuated by the armature in each of its two operated positions, a printed circuit board common to the contact units and having printed circuit conductors on both surfaces thereof, each contact unit comprising a printed circuit conductor on a first surface of the printed circuit board and an electric contact spring fixedly mounted relative to the printed circuit board and connected to a printed circuit conductor n the second surface of the printed circuit board.

3. An electromagnetic relay according to claim 2 wherein the contact spring of each contact unit is mounted on the first said surface of the board so that an end portion of that spring is displaceable by the armature to make electric connection with the contact member of that contact unit.

4. An electromagnetic relay according to claim 3 8 wherein rivet type fixin means serve to mount the con tact springs on the board and also to connect some, at least, of the contact springs through the board and each to a different one of the printed circuit conductors on said second surface of the board.

5. An electromagnetic relay according to claim 2 wherein two energizing windings embrace the two outer limbs respectively of the core, the two operated positions of the armature being obtained by energizing the two windings respectively, and a housing of electrically insulating material carries the windings and the core and is mounted on the printed circuit board.

6. An electromagnetic relay according to claim 5 wherein the housing and the board together enclose the armature, the contact members and portions of the contact springs that are for making connections to the contact members.

7. An electromagnetic relay according to claim 5 wherein the housing is detachably mounted on the board.

8. An electromagnetic relay according to claim 7 wherein edge portions of the housing abut said first surface of the board and resilient lug portions of the housing extend through apertures in the board and are sprung into engagement with said second surface of the board to mount the housing.

9. An electromagnetic relay according to claim 2 wherein two energizing windings embrace the two outer limbs respectively of the core, the two operated positions of the armature being obtained by energizing the two windings respectively, and a housing of electrically insulating material carries the windings and is mounted on the printed circuit board.

10. An electromagnetic relay according to claim 9 wherein an apertured frame of electrical insulating material stands on the board and supports the housing, and wherein a portion of the contact spring of each contact unit is clamped between the housing and the frame so that an end portion of that contact spring is displaceable by the armature through an aperture in the frame to make electric connection with the contact member of that contact unit.

11. An electromagnetic relay according to claim 10 wherein a bracket cooperates with the housing and has portions extending through apertures in the board and wherein spring means cooperates with these portions of the housing and with the board to urge the housing against the clamped portions of the contact springs.

12. An electromagnetic relay according to claim 11 wherein the core is attached to the bracket.

References Cited UNITED STATES PATENTS 2,702,841 2/1955 Bernstein 200166 2,790,875 4/1957 Bancroft 200-166 2,846,542 8/1958 Stanley 33583 3,125,652 3/1964- Richert 335-179 BERNARD A. GILHEANY, Primary Examiner.

H. BROOME, Assistant Examiner. 

